"Booster Pack" achievements
Army of Fun (15) - Without adding allies to your Skirmish team, defeat a team of 4 standard army or stronger opponents.
Bring Your Passport (10) - Win a match of Skirmish on every available map.
No Contest (10) - Defeat all of the heroes in the Skirmish Hall with premium Skirmish content.
Playing By The Rules (10) - Win a match of Skirmish with each victory condition against standard army or stronger opponents.